Experimental plasma science
The flexible heliac configuration allows the widest achievable variation of the three main parameters which control the shape of the plasma, and more importantly, its stability and confinement properties. Studies of plasma configuration involve computation of the predicted configuration from the magnet coils and their currents, experimental measurement of that shape, and investigation of its effect on equilibrium, confinement and stability. The three important shape parameters are magnetic well, related to curvature and indentation, rotational transform or twist (around the axis) per turn (along the axis), and shear, the rate of change of rotational transform with distance from the axis of the plasma.
Understanding the complex plasma-surface interaction involved in sputtering, etching, ion implantation and deposition is of great significance so that desired material properties can be tailored and optimised. Furthermore, a key challenge for fusion power is controlling transport at the boundary between the hot fusion core (>106 K) and the low temperature (103K) wall.
Our interests straddle optics, plasma physics, remote sensing, industrial applications and inverse methods. Our coherence imaging systems have found application in most of the major fusion laboratories around the world. We have recently obtained the world’s first two-dimensional images of the magnetic field inside a tokamak. The internal field is perhaps the most important of the parameters that control the fusion reactor performance.